Compounds for protection from vesicants



COMPOUNDS FOR PRGTECTION FROM VESICANTS Edgar M. Faber and Herbert A.Scruton, Baltimore, Md, and Ralph W. Peakes, Washington, D.C..,assignors to the United States of America as represented by theSecretary of War as trustee No Drawing. Application April 13, 1939Serial No. 267,720

Claims. (Cl. 117-168) (Granted under Title 35, US. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes, without the payment to usof any royalty thereon.

This invention relates in general to the treatment of cloth to render itprotective against certain liquids, gases and vapors, and moreparticularly has reference to treatment of various fabrics to renderthem resistant to the penetration of vesicant chemical warfare agents.

It is well known that mustard gas (bis (beta chlorethyl) sulfide) andsimilar vesicants penetrate ordinary clothing and produce severe burnsand many attempts have been made to provide clothing which wouldeffectively protect persons exposed to such vesicants. Impermeable suitshave been made which prevent the vesicants from reaching the wearersskin, but such clothing is uncomfortable, since it is also impermeableto air and moisture.

Developments have also produced chemicals which can be impregnated intoclothing and which permit the normal passage of air and moisture, thechemicals reacting with mustard or other vesicants to render themharmless to the skin. This method of protection is very desirable, butmany of the chemicals heretofore known for impregnating clothing havebeen so unstable in the presence of air, moisture, and sunlight thatprotection is secured for only a very limited time.

An object of this invention is to provide a method of treating clothingor fabrics to render them impervious to mustard or other vesicants whileretaining their permeability to air, the fabrics being undamaged by thetreatment.

Another object of this invention is to provide a method of treatingclothing or fabrics to render them impervious to mustard gas or othervesicants, such treatment remaining efiective for long periods of time,even after repeated laundering and exposure to air and sunlight.

Another object of this invention is to provide a method of treatingclothing or fabrics for the above purposes using an impregnatingmaterial for reacting with the vesicant agents in combination with anon-reacting binder. The binder should be chemically unreactive with theimpregnating material (active compound), be insoluble in water so as toavoid leaching and be a solvent for the vesicants, thus forming a mediumfor contact between the vesicant and the impregnite.

Another object of this invention is to provide a method of treatingclothing or fabric for the above purposes using an impregnatingmaterial, a binder and a volatile solvent. The volatile solvent is usedto secure uniform distribution of the impregnite and the binder on thecloth.

Another object of this invention is to provide a method of treatingclothing for the purpose of de-lousing the clothing and killing the eggsor nits of lice or other vermin.

Another object of this invention is to provide a method 2,929,986Patented Jan. 12, 196i) of treating clothing or fabrics for the abovepurposes wherein the clothing or fabrics are first dried to removemoisture to thereby avoid chemical reaction between water and the otheringredients and are then treated with an impregnating material whichwill react with vesicant chemical warfare agents to form relativelynon-vesicant compounds, the impregnating material and binder beingdissolved in a volatile solvent.

These and various other objects will be apparent from the followingdescription and appended claims, with the understanding that theingredients used and the steps of the process may be varied withoutdeparting from the invention.

As above indicated, this invention relates to permeable fabrics andclothing which after treatment are not greatly different in respect topassage of air than fabrics not treated. Without interfering with thenormal passage of air and perspiration, the impregnated permeable fabricabsorbs and destroys the vesicant liquids and vapors with which it comesinto contact. The present invention covers more particularly thepractical processes of using various ingredients and compounds wherebyfabrics and clothing having the properties as above described may beobtained.

Such a cloth may be obtained by the use of one of several chemicallyreactive compounds. These compounds, are preferably fixed on the clothby means of an inert binder, but in some .cases a binder is notnecessary. The compounds and the binder are preferably evenlydistributed in the fabric by the use of a volatile solvent which isvaporized from the cloth after impregnation, leaving the impregnatingmaterial and binder fixed in the fibers of the cloth.

An effective impregnating material, for the purposes of this invention,must react with mustard gas (bis(beta chlorethyl)sulfide) and otherchemical warfare vesicants quickly and completely so that no vesicantvapors can pass through or remain for an appreciable length of time inthe impregnated cloth without reacting. Furthermore, the impregnatingmaterials and the binders separately or in combination must ofthemselves be non-irritating to the skin. In addition to the above, theimpregnating materials must be as stable as possible against oxygen,carbon dioxide, sunlight and moderate washing; must have minimumdeteriorating effect on the cloth; must be substantially non-flammable;must not make the clothing too heavy, sticky, stifi or hot; the rawmaterials must be readily available; and the process must be practicaland as inexpensive as possible.

Mustard gas, which is one of the most vesicant and widely-used chemicalwarfare agents, is susceptible to halogenation.

Bearing in mind the various requisites of the impregnating agent, thebest halogenating agents have been found to be compounds having one ormore halogen atoms usually attached to nitrogen in combination with oneor more stabilizing organic radicals. In general, chlorine has beenfound to be the best member of the halogen family of elements for thispurpose and the compounds of the type described containing chlorine are'known as chloramides. Without attempting to analyze the reactionsbetween mustard gas and the chloramides, it has been found that thesecompounds are effective impregnating materials due to the presence ofactive chlotime in the molecule. The chlorine atom attached to thenitrogen has the property of chlorinating mustard gas and rendering itrelatively nonvesicant.

Since the destruction of mustard gas is accomplished by active chlorine,the protective power of a chloramide depends to a large extent on thepercentage of active chlorine which it contains. Impregnating compoundswhich have been successfully used in carrying out the present inventionare as shown below:

compound in the binder may be obtained for effective impregnation of thefabrics. The impregnating mixture thus made may be a solution ofimpregnating agent in Percent Name Formula Active Chlorine Aceto2,4,6-trichlorphenyl chloramide OH3OON(C1) 00112013 12.99 B611202,4,6-tr1chlorphenyl ehloramide CgH CON(Cl)CaH2Cl3 10. 59 p-Brombeneo2,4,6-trichlorphenyl chloramide BTOGU4OON( ODO H C]: 8. 57 Benzo2,4-d1chlorphenyl chloramide- G Ei Qs aC 2 11. 80 Aceto2,4-d1ehlorphenyl chloramide CHaOON(C o aC12 14. 87 Stearo2,4,6-trichlorphenyl ehloramid C11Ha5CON(O e 3 2 7- 1 Paltnito2,4,6-trichlorphenyl chloramide- I5HSIOON(GDCBHSC]L- 7. 54 Benzenesulfone benzyl chloramide C H SO2N(GDCH2CH 12. 592,3,5,G-tetrachlorphenylene bis-aceto chloramide Ca 14(CH3GON l 17. 782,5-dichlor 4-phenylene bis-aceto chloramide C5HZOIZ(CH3OONO1)2 21. 50Mrdrchlor 3-phenylene bis-aceto chloramide CaHzClz CHaCON O1)z 21.50Terephthal bis-2,4,6-triehlorpheny1 ehloramideu GQH4(OONGICGTT2C]B)211.98 Phthal hrs-2,4,6-trichlorphenyl chloramide CtHKCONOICBHZChh 11.98Bis-2,4,6-tnchlorphenyl chlrurea..- (OaHzOlzNCDg 14. 54 Dibenzenesulfonyl ethylene dichlord m C HSO2NC1CH2OH2NC1SOzCgHg- 17. 33Phthal-chlorimide C6H4(CO)2NO1 19. 54 Chlorortho benzoic sulfinideC6H4CO(SO2)NC1- 16.30 Quluoue dichlorimine 05H N01); 40. 05Ohlorsuccinlrnide (CI-I GOhNOI 26. 50 Dibenzoyl ethylene dichlordiamineCu sCONClCH2 zNC1COCn 6 04 Beuzoyl chlorcarbamide C H CONHOONHOl 17. 86Dibenzoyl dichlorcarbamide.. (CEHECONC1)2CO- 20. 75 I odobenzenedichloride OgH IOI 25. 83 Halazone COOHC4H4SO2NCl2. 26. 26Bis(diehlorphenylchlor)urea (C5H3012NCD2OO 16. 98

Of the above, the preferred compounds are 2,4,6-trichlorophenyl acetylchloramide, 2,4,6-trichlorphenyl benzoyl chloramide, bis dichlorphenylchlorurea, and bis 2,4,6-trichlorphenyl chlorurea. Considering allfactors, bis 2,4,6-trichlorphenyl chlorurea has been found mostsuitable, as it has the required solubility and is most stable on clothexposed out of doors.

The preferred chloramides are solids which usually require the use ofsome binding material to fix them on the cloth as mentioned above. Thisbinder shall have such properties that upon removal of the volatile partof the impregnating mixture, the impregnating material will be caused toadhere so firmly to the cloth that it will not readily be lost by wearor moderate washing; should preferably be a good solvent for mustard gasand other vesicants against which protection is desired in order to thusbring the vesicant into intimate contact with the impregnating material;should be insoluble in water so as to resist leaching action of waterand also to lend stability to the impregnating material; should be asolvent for the impregnating material or should carry it in finelydivided form; should remain permanently on the cloth withoutdeteriorating it; must not be highly flammable; and must be unreactivewith the impregnating material and not subject to chlorination.

Since the destruction of mustard gas and other vesicants depends uponthe active chlorine present in the impregnating material, it will beobvious that if the binder is subject to chlorination, the availablechlorine in the impregnating material will be used up. This difficultycan be overcome by using a binder which has been adequately chlorinatedprior to its use in impregnation, or by the use of a material which isnot subject to chlorination.

Many binders may be more or less satisfactorily used such as chlorinatednaphthalene (60% chlorine); chlorinated kerosene (59% chlorine);chlorinated coconut oil (21% chlorine); chlorinated stearic acid (30%chlorine); aluminum salts of chlorinated acids of various oils such ascotton seed oil, coconut oil, olive oil, linseed oil, castor oil,China-wood oil; nitrocellulose lacquers; synthetic resins; andchlorinated paraffin. Of these binders, chlorinated parafl'in containingto 52% chlorine is preferred. Most satisfactory results have beenobtained using paratfin containing about 42% chlorine.

Most of the compounds listed above are more or less soluble in thebinders, above given. If the compound and the binder are heated andsimultaneously thoroughly mixed, a sufficiently high percentage of thehinder or it may be partly a solution and partly a finely dividedsuspension of the agent. The impregnating solution prepared in thismanner may be directly used on the fabrics. However, one method ofattaining a more uniform distribution of the impregnite and the binderinvolves the use of a volatile solvent. This latter must be a goodsolvent for both the agent and the binder; it must be unreactive withthe agent; it must not damage the cloth; and it should be non-flammable.

The volatile solvents which more or less satisfactorily meet theserequirements are acetylene tetrachloride (tetrachlorethane);chlorobenzene; chloroform; ethylene chloride; trichlorethylene;pentachlorethane; and o-dichlorobenzene. The preferred volatile solventis acetylene tetrachloride, considering all factors to be met.

As heretofore stated, chlorination of vesicants can be effectivelyaccomplished if a compound having a high content of active chlorine canbe permanently fixed to the cloth in such manner that immediate andclose contact can be obtained between the vesicant and the compound. Inpreparing the ingredients for impregnation, approximately equal parts byweight of an impregnating compound selected from the list as given inthe table and the binder are mixed with the volatile solvent. The threematerials should be carefully and thoroughly agitated until ahomogeneous solution is obtained.

Generally, the proportions by percentage are approximately 5 to 12%impregnite, 5 to 12% binder, and 90 to 76% volatile solvent. Onespecific and preferred embodiment' comprises bis(2,4,6-trichlorphenylchlor)urea 5 to 12%, chlorinated parafiin(containing approximately 42% chlorine) 5 to 12%, and acetylenetetrachloride 90 to 76%. Excellent protection has been obtained in avariety of protective garments and other fabricated articles fromvarious grades and types of fabric using the above mixture; that is,cotton or woolen gloves, breeches, shirts, underwear, socks, leggings,hoods, coveralls, blankets, belts, canvas covers generally, etc.

Different fabrics and garments may require different percentages ofimpregnating compound and binder to attain sufficient protection undervarying conditions of use but satisfactory results are attainable usingthe above percentages. Practical tests have demonstrated that excellentprotection may be attained by using a solution comprising 5approximately 8.5% impregnite, 6.5% binder, and volatile solvent.

After the above solution has been made, the garments or fabribc arethoroughly soaked therein. Though not essential it-is preferable to havethersolution above atmospheric temperature,"-usuall-y betWeenSS-and 60C. After soaking for about minutes to insure thorough saturation whichmay be accompanied by a tumbling or other movement of the articles inthe solution, the garments or fabric are wrong out or centrifuged toremove excess solution. Of course, suificient of the solution should beallowed toremainin the garments or fabric to obtain the desiredprotection. Iftoomuch of thesolution is allowed to remain, airpermeability is reduced and the garments are too heavy for comfort.It-has been found that about 20% increase in the weight of the cloth dueto impregnation results in adequate protection against vapors ofchemical Warfareagents. After the volatile solvent has beenremoved,thisincrease in weight consists of approximately equal parts ofimpregnating compound and binder 'so that thecompound amounts to aboutof the original weight.

Next, the garments or fabric are dried:to evaporate the volatile solventwhich in the preferred embodiment is acetylene tetrachloride. This maybe accomplished by passing a current of.air.over an'dzthronglrithegarments or fabric, or the garments may be merely hung to allow thesolvent to evaporate. Preferably, care should be taken that the solventis evaporated before the garments or fabric are exposed to sun and otherstrong light, as such exposure tends to discolor the garments or fabric.

This invention has been successfully used in the largescale impregnationof clothing and fabrics by the use of a closed system substantiallysimilar to commercial drycleaning machines and equipment and includingsolvent recovery equipment. With this equipment the clothing can becompletely processed without removal from the machine. When using suchequipment, it is preferable to predry the clothing before treatment whenusing a solvent which tends to hydrolyze. In the preferred embodiment ofthe invention as above given, using acetylene tetrachloride as thesolvent, this preliminary drying is desirable to prevent corrosion ofthe machine and damage to cotton fabrics by reaction products resultingfrom hydrolysis of the solvent. The garments or fabric may be dried byany well-known method such as passing a current of heated air over andthrough them. When using the closed system as above described, thisdrying may be readily accomplished by passing heated air over andthrough the garments while they are being tumbled in the drum of themachine. In this type of equipment the volatile solvent may be recoveredfor reuse.

Treatment of fabrics in accordance with this invention may also beaccomplished by a continuous process wherein the fabric in the bolt isimpregnated. This type of equipment may include a predryer, a soakingtank, squeeze rolls or vacuum extractor, and a final dryer. Using thisequipment, the continuous web of fabric would pass in sequence throughthe equipment and could then be fabricated into such protective articlesas desired.

It will be understood, however, that this invention is not limited toany particular type of equipment or system since adequate protection hasand can be obtained by hand methods using open tubs, the garments beingstirred in the tub and excess solution being removed by wringmg.

Whether the impregnation of garments and fabrics is carried out with theaid of a volatile solvent or without such solvent, the activeimpregnating agent should be in a very finely divided state. When avolatile solvent is used and the agent has low solubility in the binder,the agent is held to the fibers of the fabric in the form of finelydivided particles. The more finely divided are the particles, the morereadily and completely will they react to destroy the vesicants. Thephysical mechanism of the reaction between the impregnating agent inchlorinated paraifin on the fabric and mustard gas appears to be asfollows. The mustard gas vapor dissolves in the chlorinated parafiin anddifiuses into contact with the particles of impregnating agent. Thechlorination of the mustard the preferred binder, i.e., chlorinatedparaffin containing about-42% chlorine, van'dit is-preferred to use avolatile solventto secureleven andthorough impregnation. How- -ever,this low solubility increasesthe stability of the agent on the cloth.Most organic compounds are considerably more susceptible to thevactionof light, air and moisture when in solution'ithan'tinrso'lidlform. Sincemost of the preferred impregnite is in solid form, it is surrounded byafilmflof chlorinated paratfin whichprotects it from air andimoisture.But since thebinder (chlorinatedparaffin in the preferred embodiment)isa good solvent for the vesicants, the activeimpregnating agent is atonce available for reaction with the vesicants.

Thefabrics origarrnentsthatare treated in accordance with this inventionare especially useful for protection of military or naval personnel whomay be exposed to vesicant chemical warfareagents such as mustard gas.Such garments may also be used by personnel whose duty it is to renovateor decontaminate areas which have been contaminated with such gases.Since mustard gas is very persistent, it is not readily dissipated andtherefore it must be removed or rendered harmless by the application ofneutralizing chemicals. The personnel employed in this work may beprotected by wearing clothing treated as herein described.

Garments rendered protective by our invention are not different inappearance and comfort from untreated garments. Air permeability is notaffected enough to make the garments uncomfortable. The weight of thegarments is increased slightly but in other respects they aresubstantially equal to untreated garments. They may be laundered withoutmaterial loss of effective protection. There is, however, a gradual lossof protective efiiciency after relatively long wear and repeatedlaundering; but such garments may be re-impregnated to renew theireffectiveness.

Such re-impregnation serves to decontaminate clothing which has beenrendered toxic by. exposure to chemical warfare agents. Also, theinitial impregnation serves to renovate contaminated clothing. Thedecontaminating action of the compounds herein described is of coursenot limited to fabrics or garments, since they are also efiioacious onany contaminated articles or materials.

The compounds herein described act to repel and kill lice or othervermin.

While we have described the preferred embodiments of this invention wewish it to be clearly understood that we do not confine ourselves to theprecise steps or ingredients set forth herein by way of illustration, asit is apparent that many changes and variations may be made therein bythose skilled in the art without departing from the spirit of theinvention or exceeding the scope of the appended claims.

We claim:

1. A method of rendering fabrics impermeable to mustard gas and othervesicants susceptible to chlorination while retaining air permeabilityof the fabric by fixing thereon vesicant destroying chloramids Whichconsists of mixing a chloramid of the group consisting of and R is achlor substituted aromatic radical with a. binder of the groupconsisting of chlorinated naphtha- '7 lene, chlorinated kerosene,chlorinated coconut oil, chlorinated stearic acid and chlorinatedparaflin in a volatile solvent from the group consisting of acetylenetetrachloride, chlorobenzene,chloroform, ethylene chloride,

trichloroethylene, pentachlorethane and o-dichloroben- 5 zene,saturating a fabric with the mixture carrying solvent and permitting thesolvent to escape from the saturated fabric whereby it is left coatedwith a chloramide-dispersed binder.

2. A method according to claim 1 wherein the binder is chlorinatedparaflin and the solvent is acetylene tetrachloride.

3. A method according to claim 1 wherein the mixture carrying solvent isprepared by mixing 5 to 12 parts by weight of the chloramide with 5 to12 parts by weight of the binder in 76 to 90 parts by weight of thesolvent.

4. A method according to claim 1 wherein the vesicant destroyingchloramide is bis(2,4,6,-trichlorphenylchlor) urea.

5. A method according to claim 1 wherein the vesicant destroyingchloramide is bis(dichlorphenylchlor) urea.

References Cited in the'fileof this patent UNITED' STATES PATENTS OTHERREFERENCES Chattaway et 'al.:' Berichte der deutschen chemischenGesellshaft," vol. 34, pages 1073-1078 (1901).

Vedders The Medical Aspects of Chemical Warfare, page 213 (1925). L

Lawson et al.: Jour. Am. Chem. Soc., vol. 49, pages 2119-3125 (1927).

Muntsch: Gasschutz v. Luftschutz, vol. 4, page 20 (1934) (ChemicalAbstracts, v01. 28, page 2431 (1934)).

1. A METHOD OF RENDERING FABRICS IMPERMEABLE TO MUSTARD GAS AND OTHERVESICANTS SUSCEPTIBLE TO CHLORINATION WHILE RETAINING AIR PREMEABILITYOF THE FABRIC BY FIXING THEREON VESICANT DESTROYING CHLORAMIDS WHICHCONSISTS OF MIXING A CHLORAMID OF THE GROUP CONSISTING OF